Felting apparatus and method



July 2, 1957 J. s. STEWART FELTING APPARATUS AND METHOD 2 Sheets-Sheet 1 Filed April 21, 1955 INVENTOR. JOHN S. STEWART ATT'YS July 2, 1957 J. s. STEWART FELTING APPARATUS AND METHOD 2 Sheets-Shae Filed April 21, 1955 INVENTOR. JOHN S. STEWART BY ATT'YS United States atent Office 2,797,624 Patented July 2, 1957 2 ,797,624 FELTING APPARATUS AND METHOD John S. Stewart, St. Charles, Ill., assignor to Hawley Products Company, St. Charles, 111., a corporation of Delaware Application April 21, 1955, Serial No. 502,869

2 Claims. (Cl. 92-57) This invention relates to a new and improved felting apparatus and a new and improved method for felting fibrous materials or filaments. The invention is especially concerned with an apparatus for making felted contoured preforms from fibers and/ or filaments, including cellulose, nylon, glass filaments, and the like.

It is conventional in making contoured articles from cellulose fibers to prepare a slurry of the fibers in water in a large vessel or tank and to accrete the fibers from the slurry on to a porous former immersed in the slurry and subject it to a vacuum during the accretion process. The type of apparatus employed and general method involved is illustrated, for example, in Newcombe, U. S. Patent 1,819,300. Other patents illustrating the conventional apparatus and procedure are Hawley U. S. 1,984,- 018, Hawley, U. S. 2,006,831 and Hawley U. S. 2,013,955. In the conventional method and apparatus, as previously indicated, the porous former on which the fibrous preform is accreted must be subjected to a partial vacuum which is provided by means of a vacuum pump connected through a hose to a chamber on the side of the forming die opposite that where the fibrous article is accreted. The former or felting die is lowered into the slurry of fibers during the felting operation and then raised in order to remove the accreted article. Water containing fine fibers is carried through the passageways which are being subjected to vacuum, tending to clog these passageways. Hose connections to the vacuumproducing device also tend to be disrupted by the constant raising and lowering of the felt forming device. Some felting action can be obtained by allowing the slurry of fibers to flow downwardly over the forming die, that is to say, without moving the forming die but this type of procedure makes it diificult to remove the formed article from the forming die because the latter would normally then be positioned below the top of the tank containing the fibrous slurry. Also, the liquid would have to be returned to the tank'for subsequent forming operations.

One of the objects of the present invention is to provide a new and improved forming apparatus in which the operation of the apparatus itself produces the required amount of suction for accreting fibers or filaments on to a porous former or felter.

Another object of the invention is to provide anapparatus of the type described in which a liquid containing the fibers or filaments to be accreted on to a porous former or felter is maintained at a substantially constant level and reutilized in subsequent forming operations.

Still a further object of the invention is to provide an apparatus of the type described in which a felted article is subjected to a partial vacuum in order to draw air through the article by a means which operates indirectly and does not move up and down into and out of the felting slurry with the felting die.

A further object of the invention is to provide an apparatus for producing articles from fibers or filaments which can be employed in a process wherein only the exact amount of fiber or filament material required to produce a predetermined preform is added to the liquid from which the preform is formed.

An additional object of the invention is to provide an apparatus of the type described which is capable of rela tively rapid production of felted preforms.

Another object of the invention is to provide a new and improved method for making preforms from cellulose fibers or from glass filaments or other similar types of materials.

Other objects and advantages of the invention will be apparent by reference to the following description in conjunctioin with the accompanying drawings in which Fig. 1 represents a side elevational view, partly in section, of an apparatus which is the best mode contemplated for the practice of the invention. 7

Figs. 2, 3, 4 and 5 illustrate diagrammatically various stages in the operation of the apparatus shown in Fig. 1; and

Fig. 6 represents a sectional view taken along the line 66 of Fig. 1.

In general, the apparatus and process of the invention involve the employment of a body of liquid in which fibers or filaments to be felted are dispersed in a predetermined amount corresponding to the amount required to make a felted article of predetermined size, shape and weight. A porous felter or former is mounted in said liquid and moved rapidly through the dispersion or slurry of fibers and/or filaments to cause the fibers and/or filaments to be deposited on said felter. During the movement of the felter the body of liquid is confined so that the liquid passes through the felter and not around it, thereby producing a pressure felting attributable to the weight of the liquid, the movement of the liquid through the perforations or openings in the felter and the hydraulic suction eifect created by the relative movement of the felter and the liquid in a confined space.

An important feature of the invention is the maintenance of a substantially constant volume of liquid. This is preferably accomplished by providing means to introduce makeup liquid on the side of the felter opposite that where the felted article is formed. In a preferred embodiment of the invention means are provided for permitting communicatioin between the lower part of the felting tank and an auxiliary vessel containing a body of makeup liquid, such as water, maintained at the same level as the body of liquid dispersion in the felting tank.

The fibers or filaments to be felted are added to the body of liquid on the side of the felter where the felting occurs and the makeup liquid is preferably added on the opposite side so that the latter does not contain fibers or filaments and the only fibers or filaments on the side of the felter opposite the felting side are very fine fibers or filaments which may pass through the openings or perforations in the felter. Inasmuch as only a predetermined amount of fibers and/ or filaments to be felted are added to the liquid and such addition is made on the felting side of the felter, the fibers and/or filaments do not substantially affect the reverse movement of the felter after the article has been formed and removed therefrom, and the operation can be repeated continuously merely by adding predetermined quantities of the fibers and/ or filaments to be felted and the makeup liquid at predetermined intervals.

A further important feature of the invention resides in the fact that it is unnecessary to apply a vacuum to the felter from an external source during the felting operation. It is an important feature of the invention, however, to cause the felter to carry the felted article to a position above the body of liquid and to apply a partial vacuum from an external source throughthe felter after the felter has reached said position outside of the liquid,

thereby to at least partially dry the resultant felted article.

More particularly, the apparatus of the invention preferably comprises a felting tank adapted to hold a body of liquid, a porous felter in said tank, supporting means for said felter mounted in said tank and adapted to move relatively with respect to the inner sides of said tank from a first position in said liquid to a second position wherein the felter is out of said liquid, means to move said felter support means from said first position to said second position, sealing means between said support means and the inner walls of said tank to maintain a fluidtight seal between the inner walls of said tank and said support means during said movement, and means to apply a partial vacuum to a space between said porous felter and the liquid level when said felter is in said second position. V In the operation of the apparatus and in the practice of the process of the invention a substantially constant volume of liquid is established in the felting tank and the porous felter is positioned in a predetermined position beneath the liquid level, preferably near the bottom of the tank. A predetermined amount of cellulose fibers and/ or glass filaments and/ or other material to be felted is added to the liquid from a point above-the liquid level and agitated to form a fibrous slurry, preferably by means of a stream of air injected into the bottom of the tank. As soon as the fibers are distributed in the liquid, the porous felter is moved upwardly. Inasmuch as there is a fluid-tight seal between the felter support means and the inner sides of the tank, the upward movement and the downfiow of the liquid through the felter causes the material in the slurry to be felted very rapidly on the porous felter. As the porous felter continues upwardly, the felted article emerges from the liquid and comes to rest in a position such that there is a space formed between the liquid level, the sides of the tank and the felting die carrying the felted article. In accordance with the invention means are provided communicating with this space to exert a partial vacuum in the space thereby causing air to be drawn through the felted article and at least partially drying it. After a suitable drying period, the article can be removed from the felter in any suitable manner and subjected to any subsequent operations which may be desired to produce a finished article such as oven drying, die drying, varnish dipping, or impregnation with a resin followed by molding.

After the removal of the felted article the felter is returned to its original position in the liquid, an addition of material to be felted is added to the liquid to form a slurry, and the operation is repeated. In this way the same liquid is used over and over again with the addition of such quantities of liquid as are required to compensate for the removal of some of the liquid by dragout. This addition is accomplished in any suitable manner, preferably by means of an automatic valve connected to a source of liquid supply and controlled by a suitable level control device.

In the specific apparatus illustrated in Fig. 1, the felting tank 1 is adapted to contain a body of liquid 2, the liquid level being shown at 3. A felting die 4 containing perforations or openings 5 is mounted on a felting ring 6 which is annular in form and is provided at its outer edge with a sealing gasket or O-ring 7 carried in a recess 8. On the upper side of the felting die 4 is a felting screen 9 having a large number of holes which are sufliciently small to prevent the passage of the material to be felted. The felted article 10 is formed on the screen 9.

The felting ring 6 is supported by a plurality of rods 11 which are bolted or otherwise fastened to a grid member 12 provided with relatively large openings 13 as shown in Fig. 6 The openings 13 permit the free passage of the felting liquid as the felter is moved therethrough.

The grid member 12 is bolted or otherwise fastened to a rod 14 which is turn is fastened to a piston (not shown) adapted to move in a cylinder 15. As shown in Fig. l the bottom 16 of the tank 1 is mounted on the top 17 of the cylinder 15. The cylinder 15 is a conventional cylinder containing a piston member adapted to be moved back and forth by means of compressed air or a hydraulic liquid. Agitation of the fibers and/or filaments in the body of liquid 2 is preferably effected by means of compressed air introduced through a pipe 18 at an angle or transversely as generally shown in Fig. l. The movement of the air stream in a generally transverse direction with respect to the body of liquid enhances the swirling or agitation action and shortens the time required to disperse the added fibers or filaments in the liquid. A conduit 19 connects through a T 20 to a drainage conduit 21 and to a second conduit 22. The latter is connected through a valve 23 to a conduit 24 which in turn is connected to conduits 25 and 26. Conduit 25 is connected to the bottom of a water level control tank 27. The conduit 26 is connected to a source of supply for water or other makeup liquid to be added to tank 1.

The addition of makeup liquid through conduit 26 is controlled by valve 28, the operation of which is controlled by a float mechanism 29. The float mechanism 29 operates in response to the level of the liquid 30 in the water level controller vessel 27. A valve 31 controls the flow of liquid from the drainage pipe 21.

The upper part of tank 1 is provided with a series of openings 32 which extend around the tank on all sides and communicate with a jacket or manifold 33 which also extends around the upper part of tank 1 and provides a space 34. One or more conduits 35 connect the space 34 provided by the manifold 33 to an external means for producing a vacuum (not shown) whereby a suction effect is produced in the space 34 which is communicated through the openings 32 to the space 36 between the level of the liquid 2 and the lower part of the felting die 4.

Fibers and/or filaments to be felted are introduced in any suitable manner, for example, by means of conduit 37. The fibers or filaments can be introduced as a preformed aqueous slurry or they can be added in a dry state.

In the operation of the apparatus as illustrated in Figs. 2, 3, 4 and 5, the first position of the felting die 18 is near the bottom of the tank 1 as shown in Fig. 2. Fibers and/or filaments 38 are introduced through a suitable conduit 37 into the body of liquid 2 as shown in Fig. 3. The air passing through conduit 18 disperses the fibers and/ or filaments to produce a slurry.

The piston rod 14 is then moved upwardly as shown in Fig. 4 causing a felted article 10 to be formed on the felting screen carried by the felting die 4.

As the piston 14 moves upwardly the felting die 4 carrying the felted article 10 moves above the liquid level as shown in Fig. 5. At this point a valve controlling the vacuum line 35 is opened causing a partial vacuum to be created in a space 34 thereby drawing air through the felted article 10 and causing water to be removed therefrom. If desired, the air can be heated in order to facilitate drying. When the felted article 10 has been sufficiently dried it is removed from the felting screen and used for any suitable purpose as previously described. If desired, the felting screen 9 (Fig. 1) can be removed with the felted article. Any suitable latch means 39 (Fig. 1) can be provided to hold the felting die 4 and/ or the felting screen 9 in place. The latch means 39 is preferably such that the felting die 4 and the felting screen' 9 can both be removed for cleaning.

The valve 23 is normally closed during the felting operation and the valve 31 is closed. Any suitable valves (not shown) controlling the vacuum lines 35 are also closed until the felted article reaches a point above the liquid level where the sealing means 7 are above the openings 32 as shown in Fig. 1. After the felted article has been removed from the felting die, the valve 23 is closed and the' cylinder is actuated to move the rod 14 to the lower position shown in Fig. 2. An additional quantity of fibers and/or filaments is then added to the body of liquid 2, the valve 23 is opened and the operation is ready to be repeated. The valve 23 can be operated manually or by means of electrical controls. Whenever valve 23 is open the liquid level control apparatus supplies the necessary quantity of makeup liquid through line 26 to maintain the volume of liquid 2 in tank 1 substantially constant.

In the particular embodiment of the invention illustrated in the drawings the felting die is a female die and in this case, for example, is adapted to form a chair body. The invention is not limited to the employment of any particular shape or size of felting die but is especially suited for the manufacture of contoured articles as distinguished from flat sheets.

The invention provides a new and improved apparatus .and process which make it possible to manufacture felted articles which are substantially uniform in a rapid and simple manner. The invention also makes it possible to manufacture such articles with .a minimum amount of waste and with a minimum amount of applied vacuum supplied from an external source. The liquid in which the fibers and/ or filaments are slurried is reused repeatedly thereby avoiding waste and also the problems which arise due to disposal of the liquid.

In the specification and claims it will be understood that the reference to a slurry of fibers means a dispersion of fibers and/or filaments in a liquid .in which the fibers and/or filaments are insoluble.

The invention is hereby claimed as follows:

1. A felting apparatus comprising a tubular felting tank adapted to hold a body of liquid, a porous felter in said tank, support means for said felter comprising an annular ring shaped member mounted in said tank :with the exterior of the ring adjacent the interior of said tank and adapted to move parallel with respect to the sides of said tank from a first position in said liquid to a second posi tion wherein the felter is outside of said liquid and said ring shaped member is spaced from the liquid level, fluidtight sealing means between said ring and the inside of said tank, means to move said support means including said felter from said first position to said second position, and means to apply a partial vacuum through the upper part of said tank to the space bet-ween said ring shaped member and the liquid level, said last named means comprising a manifold around said tank connected to .a source of vacuum and communicating by openings in the sides of said tank to said space.

2. A method of felting fibrous materials which comprises establishing a substantially constant volume of liquid in a container having an upwardly movable porous felter therein, adding a predetermined amount of a material to .be felted to said liquid on the felting side of said felter :while the latter is positioned in a predetermined position beneath the liquid level, said amount of material being just sufficient to form a predetermined article, agitating the liquid containing the added material to form a slurry of the material to be felted in the liquid, moving said porous felter upwardly through said container while maintaining liquid-tight engagement between the sides of said felter and the inner sides of said container thereby causing a felted article to be formed on the upper side of said felter, maintaining a substantially constant liquid level in said container during the formation of said article, removing water from said article on said felter by applying suction thereto through said felter as said article carried by said felter rises above said liquid level, discontinuing said suction, removing said felted article from said felter, returning said felter through said liquid to its predetermined first position and repeating the cycle of operations.

References Cited in the file of this patent UNITED STATES PATENTS 190,654 Wheeler May 8, 1877 1,819,300 Newcombe Aug. 18, 1931 2,03 8,721 Desmond Apr. 28, 1936 FOREIGN PATENTS 688,852 Great Britain Mar. 18, 1953 

